Free Tissue Transfer in Diabetic Foot Ulcers: A Systematic Review and Meta-Analysis

Objective: Free tissue transfer is a powerful reconstructive method for patients with substantial diabetic foot ulcers. This study aimed to perform an updated systematic review and meta-analysis investigating the flap characteristics, concurrent revascularisation rates, complications, and outcomes associated with free tissue transfer in diabetic foot ulcers. Methods: Two reviewers performed a systematic review of various databases since their inception, with no language restriction. Only data for free tissue transfer in non-traumatic diabetic foot ulcer patients were extracted from included studies where a heterogeneous population was studied. Outcome data were pooled using random effects meta-analysis for binomial data. Results: Of 632 studies identified, 67 studies encompassing 1 846 patients and 1 871 free flaps were included. A median of 18 patients [IQR 9, 37] per study, with a median age of 58.5 years [56, 63], were followed up for a median of 15 months [7, 25]. Most studies had serious risk of bias (n = 47 studies, 70%); sixteen (24%) had moderate risk of bias; and four (6%) had low risk of bias. The proportion of patients who underwent revascularisation was 75% (95% CI 60 -87%; n = 36 studies) with a median time of 8 days between procedures. The pooled complete flap survival, major amputation, and ambulation rates were 88% (85 -92%, n = 49 studies), 10% (7 -14%, n = 50 studies), and 87% (80 -92%, n = 36 studies), respectively. Death at individual study follow up was 6% (3 -10%, n = 26 studies). The overall certainty of evidence was very low. Conclusion: Free tissue transfer may be a useful treatment modality for recalcitrant diabetic foot ulcers in selected patients. Future studies should investigate long term functional outcomes and aim to develop patient selection algorithms to select the most suitable candidates for this procedure.